Blue & black pond dyes improve the aesthetics, while keeping the water temperatures cooler. Pond water colorants are good for the ongoing health of your pond once water clarity has been achieved with the help of other Healthy Ponds products. Safe for fish, plants, pets & humans. Simply toss the water soluble bag into the water from the shore. Within 24 hours of applying the Healthy Ponds pond water colorant, the pond will take on a beautiful appearance that will reflect the sky, & help make your Healthy Ponds AquaSpherePRO more effective. 5 oz Water soluble bag treatsup to 500, 000 gallon. To calculate pond volume: length x width x Depth x 7.5 = total gallon.